Device for spirally cutting a workpiece

ABSTRACT

The invention relates to a device ( 10 ) for cutting a workpiece ( 38 ), mounted onto an elongate rod ( 36 ), into a spiral formation. The device includes a frame ( 12 ) defining a workspace ( 14 ), and locating means ( 34 ) for locating the rod longitudinally along the workspace. A chuck ( 40 ), rotatable about an axis of rotation, is located in the workspace for holding and rotating the work piece about an axis co-axial with the axis of the rod. A carriage ( 44 ) which is transportable longitudinally along the workspace releasably mounts a cutting tool ( 46 ) extending transversely to the workspace. The device includes also transport means ( 48 ) for transporting the carriage longitudinally along the workspace and displacement means ( 34 ) for displacing the locating means, and hence in use the rod, longitudinally along the workspace. The device further includes drive means ( 52 ) for driving the transport means, the displacement means and rotatingly driving the chuck.

[0001] THIS INVENTION relates to cutting of a workpiece into a spiralformation. It relates more particularly to a device for cutting aworkpiece, mounted onto an elongate rod, into a spiral formation and toa system for cutting a workpiece, mounted onto an elongate rod, into aspiral formation. It relates also to a method of cutting a workpiece,mounted onto an elongate rod, into a spiral formation and to a spacingtool for use in the system.

[0002] The invention is expected to be particularly advantageouslyapplicable to cutting of foodstuff into a spiral formation and thatapplication will particularly be borne in mind for purposes of thisspecification.

[0003] According to a first aspect of the invention there is provided amethod of cutting a workpiece into a spiral formation, which methodincludes mounting the workpiece onto an elongate rod;

[0004] rotating the workpiece about an axis thereof co-axial with alongitudinal axis of the rod; and

[0005] feeding a cutting tool disposed transversely to the rodlongitudinally along the rod cuttingly to engage the rotating workpiece,thereby to cut the workpiece into a spiral formation.

[0006] The method may include the step of spacing loops of the spiralformation along the rod by displacing the rod, relative to an uncutportion of the workpiece, longitudinally in a direction opposite to thedirection of feed of the cutting tool.

[0007] According to another aspect of the invention, there is provided adevice for cutting a workpiece, mounted onto an elongate rod, into aspiral formation, which device includes

[0008] a frame defining an elongate workspace;

[0009] locating means for locating the rod longitudinally along theworkspace;

[0010] a chuck rotatable about an axis of rotation and located in theworkspace for holding and rotating the workpiece about an axis co-axialwith the longitudinal axis of the rod;

[0011] a carriage releasably mounting a cutting tool extendingtransversely to the workspace, the carriage being transportablelongitudinally along the workspace;

[0012] transport means for transporting the carriage longitudinallyalong the workspace;

[0013] displacement means for displacing the locating means, and hencein use the rod, longitudinally along the workspace; and

[0014] drive means for driving the transport means, the displacementmeans and rotatingly driving the chuck.

[0015] The chuck may be longitudinally fixed in the workspace and have acentral aperture for passing the rod, the locating means including twolongitudinally spaced, co-axial seats for locatingly seating ends of therod, the seats being inter-secured with an operatively fixed distancebetween them and with the chuck, having its central aperture co-axialwith the seats, being between the seats.

[0016] The transport means may include a primary leadscrew extendinglongitudinally alongside the workspace and rotatably mounted to theframe to be rotatable about an axis parallel to the chuck rotationalaxis.

[0017] The carriage may include a saddle screw threadingly engaging theprimary leadscrew and a tool mount fast with the saddle for mounting thecutting tool. Hence, relative rotation between the saddle and theprimary leadscrew results in longitudinal displacement of the carriage.

[0018] The displacement means may include a secondary leadscrew parallelto the primary leadscrew and rotatably mounted to the frame.

[0019] The seats may be inter-secured by an elongate framework havingfirst and second ends and a nut formation at or proximate the first endthereof screw threadingly engaging the secondary leadscrew to facilitatelongitudinal displacement of the framework and, hence, the seats.

[0020] The device may include at least one guide rail mounted to theframe and parallel to the secondary leadscrew, the or each guide railbeing engaged by a guide formation provided at or proximate the secondend of the framework for guiding the framework along the guide rail inthe workspace.

[0021] The frame may include a head end and a tail end in between whichthe workspace is defined.

[0022] The chuck may be provided at the head end of the frame. The guiderail may be provided in the workspace and the secondary leadscrew mayextend beyond the head end of the frame.

[0023] The cutting tool may be an elongate tool mounted at itsmid-section to the tool mount so that an operatively head end thereofleads its operatively rear end upon transportation of the carriagetoward the chuck, the device including an elongate guide mounted to thehead end of the frame and extending parallel to the primary leadscrewalong at least a part of the workspace for guiding the rear end of thecutting tool, thereby to prevent rotation of the saddle relative to theframe along the head end part of the workspace.

[0024] The chuck, the primary leadscrew and the secondary leadscrew maybe drivingly interconnected and the drive means may include a crank or arotary electric motor operatively connected to one of the chuck, theprimary leadscrew or the secondary leadscrew.

[0025] The driving interconnection of the chuck, the primary leadscrewand the secondary leadscrew may be by means of a gear train, the gearsof which are fast with the chuck, the primary leadscrew and thesecondary leadscrew, respectively.

[0026] The seat secured to the second end of the framework may bepivotally secured to the framework about an axis transverse to the atleast one guide rail, in use, to increase the fixed distance between theseats thereby to facilitate location of the rod.

[0027] According to still another aspect of the invention, there isprovided a system for cutting a workpiece, mounted onto an elongate rod,into a spiral formation, which system includes

[0028] a device as hereinbefore described; and

[0029] a spacing tool for spacing the workpiece on the rod at apredetermined distance from one end of the rod.

[0030] The spacing tool may be in the form of an elongate sheathreceivable over one end of the rod, with a passage of the sheath beingof a depth equal to the predetermined distance, and an open end of thesheath providing an abutting surface for abutting the workpiece.

[0031] The invention extends to a spacing tool for use in the system.

[0032] The invention is now described by way of example with referenceto the accompanying diagrammatic drawings.

[0033] In the drawings:

[0034]FIG. 1 shows, in three-dimensional view, a line diagram of adevice for cutting a workpiece, mounted onto an elongate rod, into aspiral formation in accordance with the invention;

[0035]FIG. 2 shows, in top plan view, the device of FIG. 1;

[0036]FIG. 3 shows, in front view, the device of FIG. 1;

[0037]FIG. 4 shows a sectional side view of the device taken at IV-IV inFIG. 2;

[0038]FIG. 5 shows a view corresponding to that of FIG. 4 with aworkpiece operatively located in the device; and

[0039]FIG. 6 shows, in three-dimensional view, a spacing tool formingpart of a system in accordance with the invention.

[0040] With reference to the drawings, a device in accordance with theinvention is generally indicated by reference numeral 10.

[0041] The device 10 includes a frame, generally indicated by referencenumeral 12, defining an elongate workspace generally indicated byreference numeral 14. The frame 12 is constituted by two uprightlaterally spaced, parallel head and tail end plates 16, 18 intersecuredby an elongate, rectangular cross-sectioned crossbar 20. The end plates16, 18 provide laterally outwardly protruding feet 16.1, 18.1 alongtheir entire widths. Ends of the crossbar 20 provide T-shaped sections22, 24 abutting inner faces of the end plates 16, 18 and providingapertures (not shown) aligned with complemental apertures (also notshown) in the end plates 16, 18 for passing bolts forming part of boltand nut arrangements 26, 28, 30, 32 by means of which the crossbar 20 isbolted to the end plates 16, 18.

[0042] The device 10 includes locating means, generally indicated byreference numeral 34, for locating an elongate rod, in this embodiment awooden skewer 36, mounting a workpiece in kebab-fashion, in thisembodiment a potato 38, longitudinally along the workspace 14. Thelocating means 34 is described in more detail hereinafter.

[0043] The device 10 includes also a rotatable chuck 40 located in alongitudinally fixed position at a head end of the workspace 14. In use,the chuck 40 (described in more detail hereinafter) abuts one end of thepotato 38 and rotates it about an axis co-axial with the longitudinalaxis of the skewer 36. The chuck 40 provides a central aperture 42 forpassing the skewer 36.

[0044] The device 10 includes also a carriage, generally indicated byreference numeral 44, mounting an elongate cutting tool 46 extendingtransversely to the workspace 14. The carriage 44 (described in moredetail hereinafter) is displaceable longitudinally along the workspace14 by means of transport means in the form of a primary leadscrew 48rotatably mounted in between the head end plate 16 and the tail endplate 18.

[0045] The device 10 further includes displacement means for displacingthe locating means 34, and hence in use, the skewer 36 longitudinallyalong the workspace 14. The displacement means is in the form of asecondary leadscrew 50 rotatably mounted to and extending beyond thehead end plate 16.

[0046] The device 10 yet further includes drive means in the form of acrank 52 for rotatingly driving the primary leadscrew 48, the secondaryleadscrew 50 and the chuck 40 which are drivingly interconnected bymeans of a gear train generally indicated by reference numeral 53.

[0047] The locating means 34 is in the form of two socket like,operatively inwardly facing co-axial seats 54, 56 spaced longitudinallyapart at an operatively fixed distance. The operatively fixed distanceis equal to the length of the skewer 36. A bearing 57 in the form of aspherical ball (the function of which is described hereinafter) islocated rotatably or fixed within the seat 54. The seats 54, 56 areintersecured by means of a framework, generally indicated by referencenumeral 58.

[0048] The framework 58 has a first end 60 spaced longitudinallyoutwardly from the head end plate 16 and provides a nut formation 62screw threadingly engaging the secondary leadscrew 50. A second end 64of the framework 58 provides two guide formations in the form of twolaterally spaced sleeves 66, 68 between the head end plate 16 and thetail end plate 18. The sleeves, 66, 68 are intersecured by means of arectangular cross-sectioned securing bar 70 which is secured to thesecond end 64 of the framework 58. The first end 60 and the second end64 of the framework 58 are-intersecured by means of an L-shaped,circular cylindrical bar 71. The sleeves 66, 68 slidably engage guiderails 72, 74. The guide rails 72, 74 are laterally spaced, extendparallel to the primary leadscrew 48, and are mounted to the head endplate 16 and the tail end plate 18. Ends of the guide rail 72 are screwthreaded and the rail 72 is mounted to the head end plate 16 and thetail end plate 18 by means of pairs of nuts 76, 78 threaded onto thescrew threaded ends of the rail 72 so as to sandwich the respective endplates 16, 18 between them.

[0049] The guide rail 74 is co-axial with and drivingly connected to thesecondary leadscrew 50. At a head end of the workspace 14, the secondaryleadscrew 50 mounts a gear 83 forming part of the gear train 53. The endplates 16, 18 mount bearings 80, 82 through which ends of the guide rail74 rotatably pass.

[0050] The seats 54, 56, in turn, are connected to the nut formation 62and the sleeve 66 respectively by means of upwardly extending,rectangularly cross-sectioned arms 84, 86. The arm 86 is pivotallymounted to the sleeve 66 so as to be pivotable in the direction of arrow88 about an axis transverse to the guide rail 74. In use, the seat 56can be pivoted to facilitate location or removal of the skewer 36.

[0051] The chuck 40 has a circular cylindrical body 88 and is rotatablymounted to the head end plate 16 by means of a bearing 90 mounted to thehead end plate 16. At an end thereof facing into the workspace 14, thechuck 40 provides a plurality of retaining blades or vanes 92 onto whichone end of the potato 38 is urged, by the cutting tool 46, to be held inuse. The blades or vanes 92 extend radially outwardly from the centralaperture 42. In between its end providing the blades or vanes 92 and thehead end plate 16, the chuck 40 mounts a gear 94 forming part of thegear train 53.

[0052] The carriage 44 is constituted by a saddle 96 screw threadinglyengaging the primary leadscrew 48, and a tool mount 98, for mounting thecutting tool 46, fast with an operatively upper part of the saddle 96.The primary leadscrew 48 extends partially longitudinally along the headend of the workspace 14. Toward a tail end of the workspace 14, theprimary leadscrew is co-axially secured to a circular cylindrical saddleguide 100. The primary leadscrew 48 and the saddle guide 100 arerespectively rotatably mounted to the head end plate 16 and the tail endplate 18 by means of bearings 102, 104. At the head end of the workspace14, the primary leadscrew 48 mounts a gear 106 forming part of the geartrain 53.

[0053] The saddle guide 100 is slidingly engaged by a sleeve 108 fastwith the saddle 96 by means of an elongate, rectangular cross-sectionedconnecting member 110. The length of the connecting member 110 is suchthat it permits a predetermined distance of displacement only of thesaddle 96 along the primary leadscrew 48, thereby to prevent the cuttingtool 46 from contacting the blades or vanes 92 in use.

[0054] The elongate cutting tool 46 is mounted at a mid-section thereofto the tool mount 98. The cutting tool 46 has a head end 112 (thepurpose of which is described hereinafter) providing a recess 114complemental to the skewer 36, in use, to receive the skewer 36. Inbetween its mid-section and its head end 112, the cutting tool 46 has anelongate cutting edge 116. The recess 114 provides a shoulder 114.1which is operatively higher than a lowest part 114.2 of the recess 114to ensure that the skewer 36 is retained within the recess 114 uponrotation of the workpiece 38 and, hence, the skewer 36.

[0055] The device 10 further includes a circular cylindrical cuttingtool guide 118 spaced operatively outwardly from and parallel to theprimary leadscrew 48 and extending along the head end of the workspace14. In use, the cutting tool guide 118 guides a rear end 120 of thecutting tool to prevent rotational movement of the saddle 96, and hencepivotal movement of the cutting tool 46, relative to the head end plate16. The cutting tool guide 118 has a screw threaded end which is screwthreadingly engaged by two nuts 122, 124 in between which the head endplate 16 is sandwiched. The cutting tool guide 118 is thus mounted tothe head end plate 16 and protrudes longitudinally inwardly therefrom.

[0056] The crank 52 is connected to an end of the guide rail 74extending beyond the tail end plate 18. The secondary leadscrew gear 83is thus a driven gear and its teeth operatively engage teeth of theprimary leadscrew gear 106 which, in turn, engage teeth of the chuckgear 94. It is to be appreciated that the drive means need notnecessarily be a crank, but could be any other appropriate drive meanssuch as, for example, an electric, possibly battery operated, rotarymotor. The device 10 may then also include a rechargeable battery. Whenthe drive means is in the form of an electric rotary motor, the device10 may include two limit switches arranged to control rotation of themotor so that displacement of the carriage 44 and, hence, the cuttingtool 46 along the workspace 14 is limited between two longitudinallyopposed points in between which the potato 38 is located and cut in use.Here, in addition, the drive means may also include a removable crank tofacilitate manual operation of the device 10 upon failure of theelectric rotary motor. The drive means could alternatively beoperatively connected to any one of the gears 94, 106.

[0057] As can been seen in FIG. 2, the cutting tool 46 extends slightlyobliquely into the workspace 14 at an angle of offset of about 1,5°relative to the head end plate 16 so that its head end 112 leads itsrear end 120 upon displacement thereof toward the head end plate 16.Instead, or in addition, a top edge 46.1 of the cutting tool 46 may leadits bottom edge 46.2 upon displacement toward the head end plate 16.Here also, if applicable, the angle of offset relative to the head endplate 16 may be about 1,5°. It is believed that the oblique orientationof the cutting tool 46 enhances the cutting operation, as hereinafterdescribed.

[0058] Referring now to FIG. 6 of the drawings, a spacing tool formingpart of a system in accordance with the invention is generally indicatedby reference numeral 126. In use, the spacing tool 126 is used to spacea workpiece 38, on the skewer 36 at a predetermined distance from oneend of the skewer 36.

[0059] The spacing tool 126 is in the form of an elongate, circularcylindrical sheath providing a longitudinal, blind bore 128. The bore128 is of a depth equal to the predetermined distance at which theworkpiece 38 should be spaced from an end of the skewer 36. An open end126.1 of the tool, i.e. that end out of which the bore 128 opens,provides an annular surface 130 which, in use, engages an end of theworkpiece 38.

[0060] In use, the workpiece 38, which as hereinbefore described is apotato, is mounted kebab-fashion onto the skewer 36. To this end theskewer 36 will typically have a sharpened end. The spacing tool 126 isreceived over that end of the skewer which is to be closest to theworkpiece 38, and is used to move the workpiece along the skewer. Inuse, the spacing tool 126 is either pushed over the skewer 36 or can beused in a hammering fashion to move the workpiece 38 along the skewer36. Upon moving of the workpiece 38 along the skewer 36, the annularsurface 130 engages an end of the workpiece 38. Naturally, the spacingtool can only move the workpiece 38 to a distance from the end of theskewer 36 equal to the depth of the bore 128.

[0061] Once the workpiece 38 is mounted at the desired position on theskewer 36, the skewer 36 with workpiece 38 is located in the seats 54,56. Location involves passing an end of the skewer 36 through the chuckcentral aperture 42 and into the seat 54. In this position the blades 92bite into the surface of the potato 38. The seat 56 is pivoted in thedirection of arrow 88 and the cutting tool 46 is positioned so that itsrecess 114 receives the skewer 36. Once the skewer and cutting tool 46are in position, the seat 56 is pivoted back to its operative position,as shown in the drawings, to receive the other end of the skewer 36. Thebearing 57 reduces friction between that end of the skewer 36 receivedin the seat 54 and an internal end wall of a bore of the seat 54 and,hence, inhibits possible longitudinal twisting of the skewer 36 in use.

[0062] The crank 52 is now rotated to displace or feed the cutting tool46 longitudinally along the primary leadscrew 48 toward the head end ofthe workspace 14 and into contact with the workpiece 38. Upon contact ofthe leading head end 112 of the cutting tool 46 with the workpiece 38,the head end 112 applies a longitudinally directed force on theworkpiece 38, thereby to urge the workpiece 38 onto the vanes or blades92 of the chuck 40. On account of the driving interconnection of theprimary leadscrew 48, the chuck 40 and the secondary leadscrew 50, thechuck 40 and the secondary leadscrew 50 are driven simultaneously withthe primary leadscrew 48.

[0063] Rotation of the chuck 40 results in rotation of the workpiece 38,thereby ensuring that the longitudinally moving cutting tool 46 cuts theworkpiece 38 into a spiral formation. Rotation of the secondaryleadscrew 50 results in displacement of the locating means 34 in adirection opposite to that of the displacement or feed of the cuttingtool 46. This displacement of the locating means 34 results indisplacement of the skewer 36 relative to an uncut portion of theworkpiece 38, thereby to space loops of the spiral formation workpiece38 along the skewer 36. A force exerted on the uncut portion of theworkpiece by the head end 112 of the cutting tool 46 is greater than africtional force of the skewer 36 being fed through the uncut portion ofthe workpiece 38, and hence, the uncut portion of the workpiece 38 isimmovable along the workspace 14 and urged onto the vanes or blades 92of the chuck 40.

[0064] When the cutting tool 46 reaches its fully displaced position asdetermined by the connecting member 110, the seat 56 is once againpivoted in a direction of arrow 88 and the cut potato 38 and the skewer36 are removed from the device 10.

[0065] Loops of the cut potato 38 are firmly secured, in spacedrelationship, on the skewer 36, and if desired, the potato 38 can thenbe cooked, e.g. by submerging it in hot oil, and seasoned after which itcan be eaten from the skewer 36.

[0066] Once the potato 38 and skewer 36 have been removed, the crank 52is displaced in an opposite direction to displace the cutting tool 46and the locating means 34 to their starting positions. The next potato38 to be cut can then be mounted on the device in the manner describedabove.

1. A method of cutting a workpiece into a spiral formation which methodincludes mounting the workpiece into an elongate rod; rotating theworkpiece about an axis thereof co-axial with a longitudinal axis of therod; feeding a cutting tool disposed transversely to the rodlongitudinally along the rod cuttingly to engage the rotating workpiecethereby to cut the workpiece into a spiral formation; and spacing loopsof the spiral formation along the rod by displacing the rod, relative toan uncut portion of the workpiece, longitudinally in a directionopposite to the direction of feed of the cutting tool.
 2. A device forcutting a workpiece, mounted onto an elongate rod, into a spiralformation, which device includes a frame defining an elongate workspace;locating means for locating the rod longitudinally along the workspace;a chuck rotatable about an axis of rotation and located in the workspacefor holding and rotating the workpiece about an axis co-axial with thelongitudinal axis of the rod; a carriage releasably mounting a cuttingtool extending transfersely to the workspace, the carriage beingtransportable longitudinally along the workspace; transport means fortransporting the carriage longitudinally along the workspace;displacement means for displacing the locating means, and hence in usethe rod, longitudinally along the workspace; and drive means for drivingthe transport means, the displacement means and rotatingly driving thechuck.
 3. A device as claimed in claim 2, in which the chuck islongitudinally fixed in the workspace and has a central aperture forpassing the rod, the locating means including two longitudinally spaced,co-axial seats for locatingly seating ends of the rod, the seats beinginter-secured with an operatively fixed distance between them and withthe chuck, having its central aperture co-axial with the seats, beingbetween the seats.
 4. A device as claimed in claim 2 or claim 3, inwhich the transport means includes a primary leadscrew extendinglongitudinally alongside the workspace and rotatably mounted to theframe to be rotatable about an axis parallel to the chuck rotationalaxis.
 5. A device as claimed in claim 4, in which the carriage includesa saddle screw threadingly engaging the primary leadscrew and a toolmount fast with the saddle for mounting the cutting tool.
 6. A device asclaimed in claim 4 or claim 5 inclusive, in which the displacement meansincludes a secondary leadscrew parallel to the primary leadscrew androtatably mounted to the frame.
 7. A device as claimed in claim 6, inwhich the seats are inter-secured by an elongate framework having firstand second ends and a nut formation at or proximate the first endthereof screw threadingly engaging the secondary leadscrew to facilitatedisplacement of the framework and, hence, the seats.
 8. A device asclaimed in claim 7, which includes at least one guide rail mounted tothe frame and parallel to the secondary leadscrew, the or each guiderail being engaged by a guide formation provided at or proximate thesecond end of the framework for guiding the framework along the guiderail in the workspace.
 9. A device as claimed in claim 8, in which theseat secured to the second end of the framework is pivotally secured tothe framework about an axis transverse to the at least one guide rail,in use, to increase the fixed distance between the seats thereby tofacilitate location of the rod.
 10. A device as claimed in claim 6 anyone of claim 8 to claim 9 inclusive, in which the frame includes a headend and a tail end in between which the workspace is defined.
 11. Adevice as claimed in claim 10, in which the chuck is provided at thehead end of the frame.
 12. A device as claimed in claim 10 or claim 11,in which the guide rail is provided in the workspace and the secondaryleadscrew extends beyond the head end of the frame.
 13. A device asclaimed in any one of claim 10 to claim 12 inclusive, in which thecutting tool is an elongate tool mounted at its mid-section to the toolmount so that an operatively head end thereof leads its operatively rearend upon transportation of the carriage toward the chuck, and in whichthe device includes an elongate guide mounted to the head end of theframe and extending parallel to the primary leadscrew along at least apart of the workspace for guiding the rear end of the cutting tool,thereby to prevent rotation of the saddle relative to the frame alongthe head end part of the workspace.
 14. A device as claimed in any oneof claim 6 to claim 13 inclusive, in which the chuck, the primaryleadscrew and the secondary leadscrew are drivingly interconnected andthe drive means includes a crank or an electric rotary motor operativelyconnected to one of the chuck, the primary leadscrew or the secondaryleadscrew.
 15. A device as claimed in claim 14, in which the drivinginterconnection of the chuck, the primary leadscrew and the secondaryleadscrew is by means of a gear train, the gears of which are fast withthe chuck, the primary leadscrew and the secondary leadscrew.
 16. Asystem for cutting a workpiece, mounted onto an elongate rod, into aspiral formation, which system includes a device as claimed in any oneof claim 2 to claim 15 inclusive; and a spacing tool for spacing theworkpiece on the rod at a predetermined distance from one end of therod.
 17. A system as claimed in claim 16, in which the spacing tool isin the form of an elongate sheath receivable over one end of the rod,the sheath having a blind bore of a depth equal to the predetermineddistance, and an open end of the sheath providing an abutting surfacefor abutting the workpiece.
 18. A spacing tool for use in a system asclaimed in claim 16 or claim 17, which is in the form of an elongatesheath having a blind bore within which an end portion of an elongaterod is receivable, the bore having a depth which corresponds to thedesired spacing between one end of a workpiece mounted on the rod and aseat of the device into which said end portion of the rod is receivable.19-23. Cancelled.